1. Field of the Invention
This invention relates to a cooking utensil which is suitable for heating by electromagnetic induction.
2. Description of the Prior Art
There is known a cooking utensil of the type which is subjected to a magnetic field induced by an exciter and heated by the heat appearing as a result of eddy-current loss. The conventional cooking utensils of this type used to be made of iron, e.g. cast iron or enameled iron, or 18Cr-8Ni or 18Cr stainless steel. The housewives, however, complained that they were heavier than those made of other materials. Moreover, the utensils made of iron were liable to rusting, and those made of enameled iron were likely to have the enamel separated from the iron.
There has been proposed the use of aluminum, which has been used for making a variety of cooking utensils, for making a cooking utensil for heating by electromagnetic induction, too. It comprises a vessel made of aluminum and having a bottom to which a different magnetic metal is bonded. It, however, still has a lot of drawbacks. The metal bonded to the bottom is liable to rusting and separation from the aluminum body. The bonding of the metal makes the utensil awkward in appearance and expensive to manufacture. Moreover, it is not comparable to a cooking pan of iron or enameled iron in heating efficiency unless its magnetic metal layer has a considerably large thickness. Therefore, it does not contribute very much to reducing the weight of an iron or stainless steel utensil.